1. Field of the Invention
The invention relates to a system for displaying electroluminescent devices, and more particularly to system for displaying tandem electroluminescent devices.
2. Description of the Related Art
Recently, with advanced development of flat panel display devices applied in electronic products, such as mobile phones, personal digital assistants, and notebook computers, there has been an increased demand for flat panel display devices which consume less power and occupy less space. Accordingly, demand for organic electroluminescent devices, having self-emitting, high luminous, wide viewing angle, fast response time and relatively simply fabrication processes characteristics, has also grown.
An organic light-emitting diode (OLED) is a light-emitting diode employing an organic electroluminescent layer as an active layer. OLED display devices have high luminescent efficiency and long operating life spans.
To further improve the performance of OLEDs and achieve a full-color image for OLED display devices, tandem OLED (or stacked OLED, or cascaded OLED) display devices, which are fabricated by vertically stacking several individual OLEDs together and driven by a single power source, has been disclosed. A conventional white tandem OLED comprises a plurality of white OLEDs (comprising R, G, and B electroluminescent layers), and at least one connecting electrode, wherein each two adjacent OLEDs are separated by the connecting electrode. However, due to the stacking sequence for each white OLED having the same RGB electroluminescent layers, emission color thereof varies with the magnitude of the driving current, thereby causing color shift over time.